A method of controlling a gas delivery apparatus including an apparatus controllable variable using an iterative algorithm to deliver a test gas (TG) for non-invasively determining a subject's pulmonary blood flow comprising iteratively generating and evaluating test values of a iterated variable based on an iterative algorithm in order output a test value of the iterated variable that meets a test criterion wherein iterative algorithm is characterized in that it defines a test mathematical relationship between the at least one apparatus controllable variable, the iterated variable and an end tidal concentration of test gas attained by setting the apparatus controllable variable, such that the iterative algorithm is determinative of whether iteration on the test value satisfies a test criterion or iteratively generates a progressively refined test value.

A breath analyzer includes a light source, a gas cell, a detection unit and a data processing unit. The light source emits infrared light of a wavelength band including an absorption line for acetone. A breath containing sample gas is introduced to the gas cell. The infrared light is incident on the gas cell. The detection unit receives transmitted light emerging from the gas cell, and outputs a sample signal value corresponding to an acetone discharge amount. The data processing unit determines an approximation formula of dependence of fat oxidation rate on acetone discharge amount in advance, and calculates a fat oxidation rate for individual sample signal values using the approximation formula. When the acetone discharge amount (microliter/min) is x, the fat oxidation rate (milligram/min) y is approximated by a following formula: y=Ax+B (where A and B are constants).

A first detector is provided with a cuff adapted to be placed on an upper arm of a subject to detect noninvasive blood pressure of the subject. At least one second detector is adapted to be placed on a part of the subject to detect at least one vital sign of the subject. A single main body is detachably provided on the cuff while being connected with the first detector and the at least one second detector. A display is provided on the main body and operable to display the non-invasive blood pressure and the at least one vital sign as measurement data. A transmitter is provided in the main body and operable to transmit the measurement data to a receiver placed in a remote location.

Quantitative colorimetric carbon dioxide detection and measurement systems are disclosed. The systems can include a gas conduit, a colorimetric indicator adapted to exhibit a color change in response to exposure to carbon dioxide gas, a temperature controller operatively coupled to the colorimetric indicator and configured to control the temperature of the colorimetric indicator, an electro-optical sensor assembly including a light source or sources adapted to transmit light to the colorimetric indicator, and a photodiode or photodiodes configured to detect light reflected from the colorimetric indicator and to generate a measurement signal, and a processor in communication with the electro-optical sensor assembly. The processor can be configured to receive the measurement signal generated by the electro-optical sensor assembly and to compute a concentration of carbon dioxide based on the measurement signal. Methods for using the systems are also disclosed including providing a breathing therapy to a patient or user.

Provided is an infection risk determination system including: a determination apparatus, including a determination unit configured to determine an infection risk degree that living bodies present in a determination target will be infected with an infection source present in the determination target, based on a carbon dioxide concentration in the determination target with an internal space for accommodating a gas containing carbon dioxide and environmental information in the determination target; and a risk control unit, configured to control at least one of an airstream, a temperature, a humidity, an intensity of ultraviolet radiation, and an amount of substances in a gas in the internal space based on a determination result of the infection risk degree; and a display unit, configured to display a control state by the risk control unit.

A non-dispersive multi-channel radiation sensor assembly includes a beamsplitter assembly, a first band-pass filter, which has a predefined first bandwidth and has a transmission maximum at a predefined first useful-signal wavelength, a first measurement-radiation useful-signal sensor, which is arranged downstream of the first band-pass filter in the beam path, a second band-pass filter, which has a transmission maximum at a predefined first reference-signal wavelength, a first measurement-radiation reference-signal sensor, which is arranged downstream of the second band-pass filter in the beam path. The beamsplitter assembly has a first irradiation region and a second irradiation region, in which irradiation regions the beamsplitter assembly is irradiated with measurement radiation. The irradiation regions are optically designed in such a way that the beamsplitter assembly deflects, in the first irradiation region, a first part of the measurement radiation onto the first band-pass filter and a second part of the measurement radiation onto the second band-pass filter.

At least one example embodiment is a method of generating a capnographic waveform, the method including: measuring carbon dioxide in exhaled gas flowing in a first flow path, the measuring creates a first set of values indicative of carbon dioxide; measuring, by the controller of the device, carbon dioxide in exhaled gas flowing in a second flow path distinct from the first flow path, the measuring creates a second set of values indicative of carbon dioxide; and creating, by the controller of the device, a capnographic waveform. Creating the capnographic waveform may including using the first set of values indicative of carbon dioxide, the second set of values indicative of carbon dioxide, and/or both the first and second sets of values of carbon dioxide.

There is provided herein a method for producing a representative CO.sub.2 waveform, the method comprising obtaining two or more CO.sub.2 waveforms, for each of the two or more CO.sub.2 waveforms determining one or more scale factors and one or more shape factors, computing, based on the one or more shape and scale factors of each of the two or more CO.sub.2 waveforms, a representative set of shape factors and scale factors representing the two or more CO.sub.2 waveforms and constructing a representative waveform based on the representative set of shape and scale factors.

Techniques for determining a volume of exhaled CO.sub.2 as a function of time using side-stream capnography, including obtaining flow dynamics measurements of a subject from a flow sensor; obtaining CO.sub.2 concentration measurements of the subject from a side-stream CO.sub.2 monitor; determining a duration of time (ΔT.sub.sl) for a sample of gas to flow from a reference point to the side-stream CO.sub.2 monitor; synchronizing in time the CO.sub.2 concentration measurement with the flow dynamics measurement, based on the determined ΔT.sub.sl; and determining a volume of CO.sub.2 exhaled as a function of time, based on the flow dynamics measurement and the synchronized CO.sub.2 concentration measurement.

A respiratory gas analyzer device (10), such as a capnograph device, is disclosed. A gas measurement component (28), such as a carbon dioxide measurement component in the case of a capnograph, is configured to measure at least one respired gas component (e.g. carbon dioxide). A pump (20) is connected to draw respired gas through the gas measurement component. A pressure gauge (30) is connected to measure pressure in an airflow pathway including the gas measurement component and the pump. An electronic pump controller (40) is programmed to start the pump in response to pressure measured by the pressure gauge satisfying a pump turn on criterion.